The age of megacities
More than half of Earth's population lives in cities—and many of them reside in megacities, the world's largest urban aggregations.
The world is a crowded place, with human population expected to reach 9 billion by mid-century. Over half of us now live in urban areas, the largest of which have swelled into giant urban agglomerations, sometimes called megacities—metropolitan areas with 10 million people or more (mapped on the globe below).
In 2020 the world will have 34 megacities, according to the United Nations , and that figure is projected to increase. Scroll down to explore the historic growth of 10 of today’s largest cities.
Will the growth of megacities worsen climate change, loss of biodiversity, and pollution? Or will the concentration of large populations in small areas provide opportunities for increased sustainability and environmental health? The answer: It depends.
Cities are traditionally centers for innovation. The World Economic Forum has outlined 10 Urban Innovations that could make cities more sustainable and economically prosperous. Scientific American's " Science for Sustainable Cities " report examines how smart urban planning and design can help people and the planet.
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